1. Field
The present invention relates to a supporter of a diffuser plate in a backlight unit, which is capable of maintain a predetermined interval between a light source and the diffuser plate.
2. Description of the Related Art
A liquid crystal display is a light receiving device which controls the amount of light incident from the outside and displays images. The liquid crystal display requires a separate backlight unit for irradiating light to the LCD panel of the liquid crystal display.
The type of the backlight unit is largely divided into an edge type and a direct type in accordance with the position of a light source to a display surface. Since the direct type backlight unit has a high utilization of light, is easy to handle and has no limit to the size of the display surface, the direct type backlight unit is being generally used for a large-scaled liquid crystal display having a size larger than 30 inches.
The direct type backlight unit does not require a light guide plate converting line light into surface light of a lamp. The direct type backlight unit includes a plurality of light sources, a reflective sheet and a diffuser plate. A plurality of the light sources are included in the lower part of the display surface. The reflective sheet reflects light irradiated from the light source to the display surface and prevents optical loss. The diffuser plate scatters light to the upper part of the light source and emits uniform light.
Here, since there exists a predetermined space between the light source and the diffuser plate, the diffuser plate sinks due to a self weight or a high temperature. In order to prevent the diffuser plate from sinking between the diffuser plate and the reflect sheet, a plurality of supporters are provided.
FIG. 1 is a partial cross sectional view of a supporting structure of a diffuser plate of a conventional direct type backlight unit.
Referring to FIG. 1, a supporter 6 is provided between a reflective sheet 4 and a diffuser plate 5. A prism sheet 8 is provided on the top surface of the diffuser plate 5. The prism sheet 8 collects the light diffused by the diffuser plate 5 and improves the luminance of an LCD panel 9 above the prism sheet 8. The LCD panel 9 displaying images is positioned above the prism sheet 8. Though not shown, a plurality of light sources are provided between the reflective sheet 4 and the diffuser plate 5 and between the supporters 6.
The supporter 6 is made of a solid material such as polycarbonate and the like so as to sufficiently prevent the diffuser plate 5 from sinking. An end of the supporter 6 contacting with the diffuser plate 5 is formed pointed such that the supporter's area viewed from the display surface is as small as possible.
However, since the end of the supporter 6 is pointed, the contact area with the diffuser plate 5 may be scratched. If a severe external impact is given to the supporting structure, the end of the supporter 6 is broken or transformed.
In order to solve the problem, FIG. 2 shows an end of the supporter contacting with the diffuser plate is made of a ductile material.
Referring to FIG. 2, a conventional supporter 10 includes a supporting member 11 and an elastic contacting member 12 contacting with the diffuser plate. An insertion hole is formed inside the contacting member 12. An end of the supporting member 11 is inserted into the inside of the contacting member 12. The contacting member 12 is made of a ductile material, reducing the possibility that the diffuser plate may be scratched when the contacting member 12 contacts with the diffuser plate.
However, in the supporter 10 having such a structure, the contacting member 12 is coupled to one end of the supporting member 11 by means of an interference fit. As a result, as shown in FIG. 3, there is a problem in that the contacting member 12 is separated from the supporting member 11 by an external impact or an external force.
When the contacting member 12 is separated from the supporting member 11, the diffuser plate is not satisfactorily supported. If the end of the supporting member 11 directly contacts with the diffuser plate, many scratches may be produced.